Current coatings used for the interior of food can containers are generally solvent-borne and are in part based on epoxy-phenolic resin combinations. Such coatings contain up to 70% of organic solvent and thus are not in compliance with current EPA regulations. Solvent recovery or incineration after coating cure represent a costly response to EPA regulations because of needed investment in new equipment and consumption of additional energy, in the incineration.
Water-borne container coating compositions such as those in which the volatile component contains greater than 75% water as solvent are very much in demand, especially for food container coating applications. In recent years, emphasis in the water-borne coating area has been directed toward resins of the polyester, acrylic and epoxy classes which can be cured with water-soluble aminoplast cross-linking compounds. We have now found that a water-borne coating composition exhibiting superior high acid and high protein resistance can be made utilizing an epoxy-phenolic resin binder system. The epoxy-phenolic resin binder system provides the combination of process and chemical resistance unmatched by the prior art coatings.